ASoC: Ensure we get an impedence reported for WM8958 jack detect

Occasionally we may see an accessory reported before we have a stable
impedance for the accessory. If this happens then reread the status in
order to ensure that the handler can take the appropriate action for the
status change.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

2 files changed, 41 insertions, 11 deletions

diff --git a/include/linux/mfd/wm8994/registers.h b/include/linux/mfd/wm8994/registers.h
index fae295048a8b..83a9caec0e43 100644
--- a/include/linux/mfd/wm8994/registers.h
+++ b/include/linux/mfd/wm8994/registers.h
@@ -1963,6 +1963,21 @@
 #define WM8958_MICB2_DISCH_WIDTH                     1  /* MICB2_DISCH */
 
 /*
+ * R210 (0xD2) - Mic Detect 3
+ */
+#define WM8958_MICD_LVL_MASK                    0x07FC  /* MICD_LVL - [10:2] */
+#define WM8958_MICD_LVL_SHIFT                        2  /* MICD_LVL - [10:2] */
+#define WM8958_MICD_LVL_WIDTH                        9  /* MICD_LVL - [10:2] */
+#define WM8958_MICD_VALID                       0x0002  /* MICD_VALID */
+#define WM8958_MICD_VALID_MASK                  0x0002  /* MICD_VALID */
+#define WM8958_MICD_VALID_SHIFT                      1  /* MICD_VALID */
+#define WM8958_MICD_VALID_WIDTH                      1  /* MICD_VALID */
+#define WM8958_MICD_STS                         0x0001  /* MICD_STS */
+#define WM8958_MICD_STS_MASK                    0x0001  /* MICD_STS */
+#define WM8958_MICD_STS_SHIFT                        0  /* MICD_STS */
+#define WM8958_MICD_STS_WIDTH                        1  /* MICD_STS */
+
+/*
  * R76 (0x4C) - Charge Pump (1)
  */
 #define WM8994_CP_ENA                           0x8000  /* CP_ENA */
diff --git a/sound/soc/codecs/wm8994.c b/sound/soc/codecs/wm8994.c
index 9cb16cc853b3..9c982e47eb99 100644
--- a/sound/soc/codecs/wm8994.c
+++ b/sound/soc/codecs/wm8994.c
@@ -3030,19 +3030,34 @@ static irqreturn_t wm8958_mic_irq(int irq, void *data)
 {
         struct wm8994_priv *wm8994 = data;
         struct snd_soc_codec *codec = wm8994->codec;
-        int reg;
+        int reg, count;
 
-        reg = snd_soc_read(codec, WM8958_MIC_DETECT_3);
-        if (reg < 0) {
-                dev_err(codec->dev, "Failed to read mic detect status: %d\n",
-                        reg);
-                return IRQ_NONE;
-        }
+        /* We may occasionally read a detection without an impedence
+         * range being provided - if that happens loop again.
+         */
+        count = 10;
+        do {
+                reg = snd_soc_read(codec, WM8958_MIC_DETECT_3);
+                if (reg < 0) {
+                        dev_err(codec->dev,
+                                "Failed to read mic detect status: %d\n",
+                                reg);
+                        return IRQ_NONE;
+                }
 
-        if (!(reg & WM8958_MICD_VALID)) {
-                dev_dbg(codec->dev, "Mic detect data not valid\n");
-                goto out;
-        }
+                if (!(reg & WM8958_MICD_VALID)) {
+                        dev_dbg(codec->dev, "Mic detect data not valid\n");
+                        goto out;
+                }
+
+                if (!(reg & WM8958_MICD_STS) || (reg & WM8958_MICD_LVL_MASK))
+                        break;
+
+                msleep(1);
+        } while (count--);
+
+        if (count == 0)
+                dev_warn(codec->dev, "No impedence range reported for jack\n");
 
 #ifndef CONFIG_SND_SOC_WM8994_MODULE
         trace_snd_soc_jack_irq(dev_name(codec->dev));